Transcript Anchorage
UPPER REMOVABLE APPLIANCE (URA) GROUP 1 Removable appliances Work by simple tipping movements of the crowns of the teeth about a fulcrum close to the middle of the tooth also allow differential eruption of teeth, for example by using bite planes. They differ from fixed appliances, which are capable of complex movements of multiple teeth, including bodily movement, root torque and rotation. Classification Removable appliance Active Passive (produce tooth movement/growt h modification) Mechanical appliances Functional appliances Retainer Space maintainer Function/Role • Interceptive treatment during mixed dentition – Eg : crossbite correction space maintainer expansion to reopen space • Facilitate of distal movement of the molars using headgear. • As an adjunct to fixed appliance tx. – Eg : anterior bite planes for overbite reduction • Maxillary restrain – Eg: maxillary intrusion splint • Assess motivation and compliance before more complex tx. INDICATIONS &CONTRAINDICATIONS INDICATIONS • Growth modification during mixed dentition • Limited (tipping) tooth movements desired (arch expansion, individual tooth mal position). • Retention following orthodontic treatment • Adjunct to fixed orthodontic appliances, • Interfere with (or prevent the development of) abnormal orofacial habits CONTRAINDICATIONS • Severe skeletal discrepancy • Upper and lower arch correlate treatment • Severe rotation • Bodily movement needed • Vertical discrepancy • Severe crowding • Very dense bone ADVANTAGES & DISADVANTAGES ADVANTAGES DISADVANTAGES • Removable for social function • Suitable for simple malocclusion • Smaller anchorage requirement • Uncompromised oral hygiene • Short chair-side time • Ease of adjustment • Require less training for management • Dependent on patient compliance • Less precise control of tooth movement • Unable to perform complex tooth movement • Difficult to control space closure • Fewer tooth movement • More difficult to correct rotation • Affect speech • Retention poor in lower arch • Prone to breakage and loss RETENTIVE Clasp ANCHORAGE ACTIVE Springs Screws Elastics Simple URA DESIGN PRINCIPLES Reciprocal Stationary Intermaxillary BASEPLATE Heat cure Cold cure Autoresin ACTIVE COMPONENTS •Springs •Screws •Elastics Z-spring • Stainless steel wire • 0.5mm diameter • Function: -proclination of 1 or 2 incisors -to correct mild rotation if only 1 helix is activated T-spring • For incisor, 0.5mm diameter stainless steel(SS) wire • For premolar, 0.6mm diameter SS wire • Function: -for proclination of incisors or premolar Finger spring • For incisor, 0.5mm SS wire • For canine and premolar, 0.6mm SS wire • Function: -for mesial or distal movement Labial bow • 0.7mm diameter SS wire • Function: -for retraction of anterior teeth Split labial bow • 0.7mm diameter SS wire • Function: -retraction of anterior teeth -to close diastema Robert retractor • 0.5mm diameter SS with sleeve • Function: -retraction of anterior teeth Buccal canine retractor • 0.7mm diameter SS wire • Function: -palatal and distal movement of mesially angulated canine Coffin spring • 1.25mm diameter SS wire • Function: -transverse expansion -buccal crossbite correction Screw • Function: -for expansion of arch -for distalization of molar teeth • 1 turn / week = 0.25mm(1/4 turn) Elastics • Rubber or latex rings • Function: -extra-oral traction -inter-maxillary traction • However, it depends largely on the patient cooperation RETENTIVE COMPONENTS • Clasps – Adam’s clasp – C-clasp (Circumferential clasp) – Lingual extension clasp – Ball clasp Adam’s Clasp • The most useful clasp in removable appliances. • It is designed to engage the MB, DB undercuts of posterior teeth. • Advantage, it does not separate teeth and has excellent retention. Adam’s Clasp fabrication • Components of Adam’s Clasp • 1- Arrow heads • 2- Bridge • 3- Tags • 4- Retentive parts • It is made of 0.7 mm diameter hard St. round wire Adam’s Clasp • Design modifications Long bridge One arrow head Solder a HG tube to the bridge Solder hook to he bridge Adam’s clasp adjustment • 1. To tighten/loosen: Adjust the arrowhead to grip the undercut of the tooth. Hold arrowhead with pliers at A and bend using finger inwards in direction shown. • 2. To adjust the height: Hold adams clasp wire the wire exits the acrlyic at pint B and bend the wire up or down to adjust verical position of arrowhead. Circumferential clasp • Circumferential clasp – Useful for second molars and canines – Easier to keep it out from occlusal contact – It is only supportive, not as retentive as Adam’s clasp – It can be adequate for a retainer, but not for an active appliance Ball Clasp • Ball Clasp – It like Adam, extends across the embrasure – Uses buccal undercuts for retention – Easy to fabricate – It is stiff that could not be extended deep into the undercuts Lingual Extension Clasp • Lingual Extension Clasp – It works only from the lingual aspect without crossing the occlusal surface or embrasures – Short loop of (0.4 mm) wire – Can be placed in the first molar second premolar lingual embrasure – Difficult to adjust – Break easily – May cause tissue irritation – Can separate teeth if active – Can be used for retainers, – not for active appliance ANCHORAGE Resistance to unwanted tooth movement BY equal in magnitude and opposite in direction Simple-active movement of few teeth versus several anchor teeth Intermaxillary- when the anchorage units situated in 1 jaw used to provide the force required to move teeth in opposing jaw Types of intra-oral anchorage Stationary-bodily movement of 1 group of teeth against tipping of another Reciprocal-when 2 teeth or 2 sets of teeth move to an equal extent in an opposite direction BASEPLATE • It must be: -hold components -clear acrylic = heat cure, cold cure polymethylmethacrylate, autoresin -comfortable -good fit -can be active as additional functions-act as bite plane References • http://www.retainerlab.com/Pages/Springs.htm • http://universal-dental-techniques.com • http://www.intelligentdental.com/2011/10/02/agapbetween-yourupper-front-teeth/ • http://dentallecnotes.blogspot.com/2011/10/note-on-activecomponents-of-removable.html • http://o-atlas.de/eng/kapitel5_156.php • http://askanorthodontist.com/braces/what-do-the-elastic-rubberbands-on-braces-do/ • Lecture by Dr. Norzakiah(principles of removable appliance therapypart 1) • Lecture by Dr. Fitri Octavianti(types of orthodontic appliances)